Tehran , Iran -LRB- CNN -RRB- -- Iranian opposition leader Mehdi Karrubi has not been seen for six weeks and may be facing psychological torture by the government , activists claimed Monday , citing sources in the country .

`` We are extremely concerned for the health and well-being of Karrubi , who is 74 years old , and no one has heard from him for six weeks , not his wife , any family or associates , '' said Hadi Ghaemi , the director of the International Campaign for Human Rights in Iran .

His wife said she had not had any contact with him since July 16 , the campaigners said , citing the opposition leader 's official website .

Ghaemi alleged that Karrubi is `` surrounded by a team of psychiatrists working with his captors '' to try to manipulate him into a televised confession . He cited `` a credible source from inside Iran , '' without saying who it was .

An opposition website said February that both Karrubi and Mir Hossein Moussavi , another opposition leader , had been detained .

The website , Kaleme , citing `` trusted sources , '' reported that the men and their wives had been arrested and taken to Tehran 's Heshmatieh prison .

The semi-official Fars news agency denied the report , citing an unnamed judiciary source , but it had earlier said that the government had restricted the movements and communications of both men .

The two , who are both former government insiders , both ran for president against Mahmoud Ahmadinejad in the disputed 2009 election that led to months of protests and a government crackdown on the opposition .

Iranian authorities rounded up opponents afresh in February , as revolutions swept the region .

Iran media said Monday that that Karrubi was being kept in an unknown location but did not include any comments from Iranian officials .

International journalists have been limited in their ability to gather news in Iran , where the government has squelched the media and maintains tight control over state-linked news organizations .

@highlight

Mehdi Karrubi has not been in contact with his wife since July 16 , she says , according to campaigners

@highlight

Activists fear he is under psychological pressure to make a televised confession

@highlight

He and Mir Hossein Moussavi came under restrictions in February

@highlight

Iranian officials have apparently not commented on the reports about Karrubi